Plant for closure of foundry molds

ABSTRACT

A plant for closure of foundry molds which comprise upper and lower halves, said plant comprising essentially a rolling track sloping at a shallow inclination, which by gravity conveys the lower halves of the molds to a positioning and closing station and which removes the molds after closure, a framework arranged over said rolling track and acting as a support for a device for transfer of the upper halves of the molds, coordinated with a device for infeed of the said halves, and means of ensuring the displacement of the transfer device in two directions.

[ lFeb.8, 1972 United States 1' Darbonville 7!\ own 33 MBB 44 66 1 1 [54] PLANT FDR CLOSURE OF FOUNDRY MOLDS [72] inventor:

Young Me In m c a HT 002 776 999 111 Mm 885 527 M77 E u R 5 9 0 Pierre Justin Auguste Durbonvill Anatole France France, 45 FIeUTY-ICS-AUbI'aiS, Primary Examiner-J. Spencer Overholser Assistant Examiner-John S. Brown Attorney-Wenderoth, Lind & Ponack [22] Filed: May 25, 1970 ABSCT 211 App]. 1%.; 40,053

A plant for closure of foundry molds which comprise upper in two directions.

11 Claims, 17 Drawing figures References Cited UNITED STATES PATENTS 3,516,475 6/1970 Dougherty....,..........................164/37 A V l M Pmmwrm 81972 3.640 335 FIG. 1

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PLANT FOR CLOSURE OF FOUNDRY MOLDS BACKGROUND OF THE DISCLOSURE The present invention relates to a plant for closing foundry molds or frames.

As known, the two halves of a foundry mold, each filled with rammed sand and having a molding impression, must be assembled tightly one against the other prior to the casting of the metal, and generally secured in this position by at least two centering and locating bars referred to as studs or pegs, which fit into the rings or eyes borne by the lugs of each of the said upper and lower halves of the mold.

This closing operation, performed after molding which is carried out either manually or by machine, was performed by hand until now, a conveyor bringing the lower parts of the molds consecutively to a turning platform allowing each lower half of a mold to be directed in such manner as to facilitate assembling the same with the upper half held or guided manually by the worker facing towards the conveyor.

This work was tiring and required rather a lot of time, which limited the output. Moreover, in the case of casting frames of large size and thus of relatively great weight, the handling operation performed by means of a suspension device required great concentration from the worker, to enable the same to position the upper half of the mold precisely in plumb with the lower half on which it is intended to rest.

The present invention eliminates these drawbacks and relates to a plant for closure of foundry molds which allows of automatic, rapid and precise operation, and which can be adapted to fit on the egress of existing molding machines.

SUMMARY OF THE INVENTION The plant according to the invention essentially comprises, in combination, a rolling track with rollers positioned at a shallow slope which by gravity conveys the lower halves of the molds to a positioning and closing station and which removes the molds after closure, a framework fitting on the said rolling track and acting as a bearer for a device for transfer of the upper halves of the molds, coordinated with a device for infeed of the said halves, and means of ensuring the displace ment of the transfer device in both directions.

The invention equally relates to a foundry mold or frame more particularly applicable in the aforesaid plant.

Other characteristics and advantages of the invention will be clear from the following description of one form of construction of a plant for closure of foundry molds.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in perspective of the plant with the upper half of a mold placed on the rolling track leading to the rollers of a transfer platform.

FIG. 2 is a view in perspective of the rear of the plant more particularly showing a rollered rolling track arranged on the transfer platform and serving the purpose of consecutively feeding the upper halves of molds over the corresponding lower halves fed in by gravity, on the rolling track, to the positioning and closing station.

FIG. 3 is a view in perspective of the front of the plant, showing the transfer platform with its two parallel rows of tipping rollers.

FIG. 4 is a schematic plan view of the plant comprising a device for preliminary alignment of the lower halves of the molds on the rolling track.

FIG. 5 is a schematic elevational view corresponding to that of FIG. 4.

FIG. 6 is a schematic elevational view which, in the initial position of the transfer platform, shows the position occupied by the rollers carrying the upper half of the mold.

FIG. 7 is a schematic elevational view illustrating the withdrawal of the supporting rollers, prior to the relifting of the platform into the position illustrated in FIG. 6.

FIG. 8 is a schematic elevational view of a closed mold situated in the positioning and closing station, at the beginning of the ascent of the transfer platform.

FIG. 9 is a plan view corresponding to that of FIG. 8, the closed mold having been moved out on the rolling track in the direction shown by the arrow.

FIG. 10 is a diagrammatical view of the electric circuit controlling the reversible electromagnetic valve actuating the double-acting ram operating the transfer platform.

FIG. 11 is a view from above of a horizontal bar bearing the end-of-travel switch actuated by the ring of the upper half of the mold.

FIG. 12 is an enlarged scale elevational view of the device for preliminary alignment of the lower halves of the molds, which is diagrammatically shown in FIG. 4.

FIG. 13 is a schematic plan view corresponding to that of FIG. 12.

FIG. 14 is an enlarged scale elevational view showing the device for holding the lower halves of the molds in the positioning and closing station, the said device being in the locking position.

FIG. 15 is a schematic view illustrating the driving of the valves of the electromagnetic valve alternately feeding the double-acting ram serving the purpose of handling the transfer platform.

FIG. 16 is an enlarged scale view in profile of the lug and ring of the mold or frame apparent in FIG. 3.

FIG. 17 is an overall view in perspective of a mold or frame such as that illustrated in FIG. 3, but comprising a ring standing proud on either side of the lug of the frame.

DESCRIPTION OF THE PREFERRED EMBODIMENT The plant according to the invention is intended to transfer from a station A to a station C, lower casting frames 1, and to perform a closure between these and upper frames 2 coming from a station B (see FIGS. 4 and 5).

The stations A and B may consist of molding machines.

The lower casting frames 1 are conveyed by gravity from the station A to the station C by means of a shallow slope rolling track formed by rollers 3.

Between the station A and the station C is interposed a device for preliminary alignment of the lower frames, which is marked 4 as a whole, and which will be dealt with in greater detail hereinafter, with reference to FIGS. 12 and 13. The upper casting frames 2 pass from the station B to the station C while sliding horizontally on a rolling track formed by two rows of rollers 5. These rows of rollers 5 are extended by two rows of rollers 6 in unit with a platform which is vertically displaceable in a supporting framework over the rolling track with rollers 3 and serving the purpose of transferring one half 2 of a mold over a half 1. This supporting framework essentially comprises four uprights 7, 8, 9 and 10 firmly coupled in pairs by lower crossbars ll, 12, 13 and 14 and upper crossbars 15, 16, 17 and 18.

As for the displaceable transfer platform, it is apt to slide by means of sleeves 19, 20, 21 and 22 on vertical guiding rods 23, 24, 25 and 26 fastened to the framework.

The sleeves l9 and 20 are interconnected at their upper part by a tube 27 and at their lower part by an U-shaped yoke or stirrup 28. The sleeves 20 and 21 are interconnected by means of two tubes 29 and 30, the sleeves 21 and 22 by means of tubes 31 and 32, and the sleeves 22 and 19 by means of tubes 33 and 34. As for the rollers 5, they are installed on flat bars 35 carried by uprights 36 and 37 which are firmly joined to the framework by stays 38 and 39. Shelves 40 and 41 carry bins containing, for example, studs 42 intended for insertion into the rings 43 in the lugs 44 close to the handles of the upper halves 2 of the molds, as illustrated in FIG. 1. The ring of the lower halves 1 of the molds is marked 45 and the corresponding lug is marked 46 (see FIG. 3 in particular).

The rollers 3 are installed in freely rotatable manner in two angle-irons 47 and 48 firmly joined to the crossbars 12 and 14. The tubes 29 and 33 are firmly joined by a crossbar 49 acted upon in its middle by a connecting rod 50 which has its other extremity connected to the rod 51 of a ram 52 fed for lifting purposes by a compressed air pipe 53 leading to the valve 54 of an electromagnetic valve 55 comprising two pipes (FIG. The second pipe 56 of this electromagnetic valve is controlled by means ofa valve 57, The pipe 56 for the lowering of the double-acting ram, which is apparent from FIG. 15, has not been illustrated in FIG. 1 to avoid complication. The ram 52 is carried by a yoke comprising two oblique branches 58 and 59 which are secured to the corresponding crossbars l6 and 18 of the framework.

As apparent from FIG. 2, reinforcing plates 60 and 61 which are welded to the tube 27 on the one hand and to the corresponding guiding sleeves l9 and 21 on the other hand, are arranged at the point at which the transfer platform does not comprise a crossbar to allow of passage of the upper half 2 of the mold with its stud 42.

Tipping bars 62 and 63 carrying the rollers 6 are journaled at their extremities in a perforation wrought in a lug 64 welded to the displaceable platform. On the tipping bars 62 and 63 are installed earns 65 and 66, which remain to be dealt with further on, and which cooperate with vertical abutment rods 67 and 68 fastened on a crossbar 69 connecting the crossbar l6 and 18 of the framework. Counterweights 70 and 71 tend to cause outward tipping of the bars 62 and 63 carrying the rollers 6 and the upward displacement of the earns 65 and 66 in unit with the said bars 62 and 63.

As apparent from FIG. 10, the electric control circuit comprises a supply line 72 with two conductors feeding the electromagnetic valve 55, a contactor 73 actuated by the tipping bar 62 carrying the rollers 6 and an end-of-travel contactor 74 whose pushrod 75 is actuated by the ring 43 of each upper half 2 of a mold. This end-of-travel contactor 74 is supported by an adjustable-level horizontal bar 76 which is arranged in vertically displaceable manner by means of two sheaths 77 and 78 sliding on the guiding rods 79 and 80 fastened on the transfer platform.

The result thus obtained is that it is possible to adjust the position of the contactor 74 as a function of any prevailing height of the mold whose ring 43 is situated at greater or lesser height, and that too violent an impact of the bar 75 on the lug 44 of the upper half 2 of the mold is prevented at the end-oftravel position.

To ensure the interruption of the circuit illustrated in FIG. 10, in the lower position of the platform which is illustrated in FIG. 7, and by virtue of this fact to cause the reversal of the electromagnetic valve 55 illustrated in detail in FIG. 15, the contactor 73 which is arranged in series with the end-of-travel contactor 74 actuated by the ring 43 of the upper half 2 of the mold is closed by the pressure exerted on it in the vertical position of the rollers 6, by one of the tipping bars bearing the said rollers, that is to say the bar 62.

Furthermore, to ensure after the unloaded ascent of the platform, in preparation for another operating cycle of the plant, the closing of the contactor 73 coupled in series with the contactor 74 actuated by the upper half 2 of the mold-in fact by the ring 43 of the said mold-the framework carrying the transfer platform has arranged on it two abutment rods 67 and 68, each cooperating with a cam 65 respectively 66, in unit with one of the tipping bars 62, respectively 63, bearing the rollers 6 for support of the upper half2 of the mold.

After the closing of a mold, that is to say after laying down the lower half 1 of the mold, the withdrawal of the rollers 6 is intended to allow the platform to rise again, Each tipping bar 62 and 63, bearing the rollers 6, is actuated by the counterweights 70 and 71.

FIG. 11 shows the bar 76 bearing the contactor 74 actuated by the molds. For guiding the same vertically, this bar comprises two sheaths 77 and 78. To complete the centering of the upper half 2 of the mold before the ring 43 of the same actuates the pushrod 75 of the contactor 74, and moreover to prevent a possible rebound after the closing of the end-oftravel contactor 74 controlling the lowering of the transfer platform, this contactor 74 is preceded by two magnetized ramps 81 and 82. A precise application of the ring 43 against the pushrod 75 of the contactor 74 it actuates, is thus obtaincd.

Before placing the upper half 2 of the mold on the lower half 1, it is essential for this latter to be in a precise position allowing of insertion of the studs 42. To this end, the plant comprises a device for positioning and keeping the molds in the closed position. This device consists of two oblique ramps 83 and 84 guiding the rings 45 of the lower halves 1 of the molds and leading each of these into abutment against a bolt 85, respectively 86, arranged to tip downwards (FIG. 8) to release the molds closed, under the action of an articulated linkage 87, 89, 88 returned to the locking position by a counterweight 90 and actuated in the direction of ascent of the transfer platform by the lower bar 28 of the yoke or bow arranged at the lower part of the said platform, by means of an operating rod 91 which is downwardly withdrawable against the action of a return spring 92 (FIG. 14) and in the other direction causes the downward pivoting of the locking bolts of the closed mold.

As has already been stated (FIG. 4), this positioning and holding device is preceded by a system 4 allowing of preliminary alignment of the halves l of the molds on the rolling track 3. The rollered rolling track 3 is coordinated with a device for preliminary alignment of the lower halves of the molds which is formed (FIGS. 12 and 13) by two aligning fingers 93 and 94 pivoting in a horizontal plane, at either side of the rollered rolling track 3 at the level of the rings 45 of the lower parts 1 of the mold being displaced on the said rolling track 3, each aligning finger being in unit with a level branch 95, respectively 96, directed in the opposite direction to the lever branch coordinated with the other aligning finger, whereas the extremities of the two lever branches 95 and 96 directed in opposite directions are interconnected in articulated manner by means ofa linking bar 97.

As has been stated, the plant according to the invention operates by means of the double-acting ram 52 supplied through the pipe 53, for lifting purposes, and through a pipe 56, for lowering purposes, each of the said pipes being controlled by the valves 54 and 57 of the electromagnetic valve 55 illustrated in detail in FIG. 15.

As apparent, this electromagnetic valve 55 comprise a moving core 98, comprising a rod 99 connected in jointed manner at 100 to a lever 101 equipped with a counterweight 102 and having two bosses 103 and 104 intended to exert thrust on the heads 105 and 106 for operation of the valves 57 and 54 feeding the pipes 56 and 53, respectively.

In the molding frame illustrated in the drawings and more specifically in FIGS. 16 and 17, the cylindrical ring 45 is arranged in the lug 44 of the frame 1 while projecting from the same over a relatively substantial height allowing of the cooperation of the said ring 44 with the guiding and abutment means incorporated in the plant and allowing of the alignment and centering of the said frames at the different stations.

The projection of the ring 45 for the guiding and centering of the half 1 of the frame or mold on which it is fitted, does not reach the plane ofjunction with the half of the mold or molding frame with which it is coordinated.

The operation of the plant described and illustrated is the following:

In the upper position of the transfer platform and in the absence of an upper half 2 of a mold not inserted as yet (FIG. 1) the contactor 74 is open and no current is consequently fed to the electromagnetic valve 55. Owing to this fact, the core 98 has returned into the armature 107 and the lever 101 pivoting around the point 108 under the action of the counterweight 102, exerts a thrust through its boss 104 on the actuating head 106 of the valve 54 supplying the pipe ensuring that the ram 52 is kept in the raised position and consequently that the platform is kept in the raised position. Since, owing to this fact, the abutment rods 67 and 68 are in abutment on the earns 65 and 66 of the bars 62 and 63 bearing the rollers 6; these latter with their bars, are in the vertical position.

It follows that the contactor 73 depressed by the bar 62, is closed and that the current circuit 72 supplying the electromagnetic valve 55 is then interrupted only by the opening of the contactor 74.

When the upper half 2 of the mold passes from the rollers 5 on to the rollers 6 and continues its path until its ring 43 exerts thrust on the pushrod 75 of the contactor 74, the circuit of the electromagnet of the electromagnetic valve 55 is energized, expels the plunger core 98 which causes the lever 101 to tip against the action of the counterweight 102 around the point 108, whereas the corresponding boss 103 exerting thrust on the head 105 of the valve 57 causes the inflow of fluid into the pipe 56 and from the latter into the upper partnot illustrated in FIG. l-of the ram 52. Owing to this fact, the rod 51 of the ram 52 downwardly thrusts the connecting rod 50 articulated on the crossbar 49, which causes the lowering of the transfer platform carrying the half 2 of the mold. When this half 2 of the mold reaches the half 1, after insertion of the studs 42 in the rings 45 of the lower half which had previously been conveyed to the transfer station of a conventional conveyor plate 109 comprising locating pegs 110, the platform continues its travel and the rollers 6 carried by the bars 62 and 63 cease to carry the upper half 2 of the mold and, by abutment of the lug 414 of the upper half 2 of the mold, the bar 76 carrying the contactor 74 frees the pushrod 75 of the said contactor from the ring 43 of the upper half of the mold. At the same time, under the action of the counterweights 70 and 71, the bars 62 and 63 carrying the rollers 6 tip outwards, freeing the return path of the platform, which simultaneously causes the opening of the contactor 73 arranged in service with the contactor 74. Owing to this fact, the current supplying the electromagnet of the electromagnetic valve 55 is interrupted and this latter is reversed owing to the fact that the counterweight 102 (FIG. by means of the lever 101 and of its boss 104, ensures the activation of the valve 54 which allows the compressed air arriving at 111 to pass and ducts the same through the pipe 53, to the base of the ram 52, which ensures the raising of the transfer platform,

During the preceding descent of the platform, the lower bar 28 of its yoke had passed below the withdrawable operating rod 91. During the raising of the platform, the bar 28 of the yoke then lifts the said rod 91 which, articulated at 112, comes into abutment (FlG. 14) against a peg 113 arranged on the bolt 85. This latter, by tipping downwards, causes the lowering of the connecting rod 87 acting on the lever 89 pivoting around the point 113 and causes the connecting rod 88 to rise. In this displacement, this latter causes the bolt or look 86 to pivot downwards. Thus, the two bolts 85 and 86 release the closed mold 1, 2 which is then removed on the rolling track 3 while making room for the arrival at the positioning and holding station of another lower half 1 of a mold which had initially been aligned by the preliminary alignment device 4. When the platform reaches the end of its upward stroke, the abutment rods 67 and 68 cause the tipping of the cams 65 and 66 integral with the bars 62 and 63 carrying the rollers 6. Owing to this fact, these latter are placed in the vertical position again and are ready to receive the next upper part of a mold, the tipping bar 62 simultaneously having closed the contactor 73 arranged in series with the contactor 74. Accordingly, as soon as the contactor 74 is actuated by the next upper part 2 of a mold, the electromagnetic valve 55 will be reversed and another cycle will begin.

It is evident that the invention has been described and illustrated purely by way of explanation and in no way of limitation, and that a variety of modifications of detail could be made in the form of embodiment specified without thereby exceeding the scope of the invention, as defined by the appended claims.

In particular, the uprights and crossbars could be formed by means of tubes rendering it possible to vary the spacing of the tipping bars carrying the supporting rollers. Moreover, instead of controlling the plant by means of an electromagnetic valve, different pneumatic switches could be incorporated for direct operation of the ram. Finally, the positioning device also arranged l'or securing the lower halves of molds at the closing station could he wrought analogously to the station for preliminary alignment of the frames arranged on the shallowslope roller conveyor, the locking bolts being apt to have a different structure and to be actuated direct by a ram or the like, coming into action after the closing of the mold.

As for the mold as such, its pegging ring or eye projecting from the lug of the half of the mold or frame could have a different profile, for example an elliptical, polygonal or frustoconical single or double profile.

Iclaim:

ll. Plant for closing molds which comprise upper and lower halves comprising a positioning and closing station, a rolling track sloping at a shallow inclination to convey by gravity the lower halves of the molds to said positioning and closing station, a framework over said rolling track, transfer means sup ported on said framework to position the upper halves of the molds over the lower halves in said station, feeding means to feed said upper halves to said transfer means, control means to effect displacement of the transfer means in two directions, said transfer means comprising a platform vertically displaceable in both directions and consecutively receiving the upper halves of said molds to be placed on the lower halves in said positioning and closing station, two tipping bars, rollers for said platform carried by said bars which are laterally withdrawable to allow said platform to be raised in an empty state, said bars being aligned with said feeding means which comprises two parallel rows of rollers in extended alignment with the rows of platform supporting rollers to deliver the upper parts of the molds to the transfer means.

2. Plant according to claim 1, and comprising means for effecting vertical displacement of said transfer platform, said means comprising a double-acting ram and a reversible electromagnetic valve controlling said ram, and two contactors arranged in parallel in a supply circuit of the said electromagnetic valve being provided to control said valve.

3. Plant according to claim 2, in which said upper half of each mold comprises end rings and assembling studs and said lower half of each mold comprises end rings for alignment with the studs of the upper half, and an end-of-travel contactor which controls said electromagnetic valve is operated by the end ring of an upper half to lower said transfer platform when the upper half is in correct alignment with said lower half in said positioning and closing station.

4. Plant according to claim 3, in which said electromagnetic valve is manually controlled, a feed valve controls the raising and the securing of said ram in the raised position, and counterweight acts directly on said feed valve when said electromagnetic valve is closed.

5. Plant according to claim 4, in which an adjustable-level horizontal bar carries said end-of-travel contactor, and two sheaths sliding on guide rods fastened to the transfer platform effect vertical displacement of said horizontal bar.

6. Plant according to claim 5, in which a further contactor arranged in series with said end-of-travel contactor is closed by the pressure exerted upon it in the vertical position of one of said tipping bars.

7. Plant according to claim 6, in which two vertical abutment rods and cooperating cams connected with the tipping bars are provided on said framework supporting the transfer means.

8. Plant according to claim 7, in which a counterweight acts on each tipping bar.

9. Plant according to claim 8, in which two oblique magnetized ramps which retain the rings of the upper halves of the molds precede said end-of-travel contactor.

10. Plant according to claim 3, in which said transfer means comprise two oblique ramps which guide the rings of the lower halves of the molds against a tipping bolt which is provided for release of the closed molds, a locking articulated linkage incorporating a return counterweight being provided to actuate said bolt, said linkage being actuated in the lifting direction of the transfer platform by means of the lower bar of the yoke arranged at the lower part of the said platform, by means of an operating rod which is downwardly withdrawable against the action of a return spring, and in the other direction causes the downward pivoting of the bolts securing the closed mold.

molds on said track, each aligning finger being connected with a lever and the levers extending in opposite directions to each other, and a linking bar interconnecting the extremities of the two levers. 

1. Plant for closing molds which comprise upper and lower halves comprising a positioning and closing station, a rolling track sloping at a shallow inclination to convey by gravity the lower halves of the molds to said positioning and closing station, a framework over said rolling track, transfer means supported on said framework to position the upper halves of the molds over the lower halves in said station, feeding means to feed said upper halves to said transfer means, control means to effect displacement of the transfer means in two directions, said transfer means comprising a platform vertically displaceable in both directions and consecutively receiving the upper halves of said molds to be placed on the lower halves in said positioning and closing station, two tipping bars, rollers for said platform carried by said bars which are laterally withdrawable to allow said platform to be raised in an empty state, said bars being aligned with said feeding means which comprises two parallel rows of rollers in extended alignment with the rows of platform supporting rollers to deliver the upper parts of the molds to the transfer means.
 2. Plant according to claim 1, and comprising means for effecting vertical displacement of said transfer platform, said means comprising a double-acting ram and a reversible electromagnetic valve controlling said ram, and two contactors arranged in parallel in a supply circuit of the said electromagnetic valve being provided to control said valve.
 3. Plant according to claim 2, in which said upper half of each mold comprises end rings and assembling studs and said lower half oF each mold comprises end rings for alignment with the studs of the upper half, and an end-of-travel contactor which controls said electromagnetic valve is operated by the end ring of an upper half to lower said transfer platform when the upper half is in correct alignment with said lower half in said positioning and closing station.
 4. Plant according to claim 3, in which said electromagnetic valve is manually controlled, a feed valve controls the raising and the securing of said ram in the raised position, and counterweight acts directly on said feed valve when said electromagnetic valve is closed.
 5. Plant according to claim 4, in which an adjustable-level horizontal bar carries said end-of-travel contactor, and two sheaths sliding on guide rods fastened to the transfer platform effect vertical displacement of said horizontal bar.
 6. Plant according to claim 5, in which a further contactor arranged in series with said end-of-travel contactor is closed by the pressure exerted upon it in the vertical position of one of said tipping bars.
 7. Plant according to claim 6, in which two vertical abutment rods and cooperating cams connected with the tipping bars are provided on said framework supporting the transfer means.
 8. Plant according to claim 7, in which a counterweight acts on each tipping bar.
 9. Plant according to claim 8, in which two oblique magnetized ramps which retain the rings of the upper halves of the molds precede said end-of-travel contactor.
 10. Plant according to claim 3, in which said transfer means comprise two oblique ramps which guide the rings of the lower halves of the molds against a tipping bolt which is provided for release of the closed molds, a locking articulated linkage incorporating a return counterweight being provided to actuate said bolt, said linkage being actuated in the lifting direction of the transfer platform by means of the lower bar of the yoke arranged at the lower part of the said platform, by means of an operating rod which is downwardly withdrawable against the action of a return spring, and in the other direction causes the downward pivoting of the bolts securing the closed mold.
 11. Plant according to claim 3, and comprising means associated with said rolling track for preliminary alignment of the lower halves of the molds, said means comprising two aligning fingers which pivot in a horizontal plane at either side of said track at the level of said rings on the lower parts of the molds on said track, each aligning finger being connected with a lever and the levers extending in opposite directions to each other, and a linking bar interconnecting the extremities of the two levers. 